To replicate:
Add Stories to current sprint
Start Sprint
Create Sub-tasks
Complete Story
View Sprint Report
Completed Stories show value of

See attached screen capture.

This has now become a major reporting issue and a black eye for me with the PMO who is apprenhesive to Agile and we were using Jira Agile and it's Sprint and Version reports to demonstrate how well we can predict completion dates vs using Clarity or MS Project. Now I do not know how to explain this problem. Pease let me know how to fix or if it is user error.